Dear Friend,
As for as industry is concerned for 250 workers canteen may be provided with standards as they want as an IT industry is concerned it is your choice of providing canteen facilities either wet or dry canteen, the space requirement is required to be provided working out with the canteen facility who is interested and work with you, also, you have to mention time, foods need provided, cost, quality, rent, electrical charges for the usage, your company contribution, co-ordination with the canteen authorities for inspection of the canteen, cleanliness, quality of items used for preparing the food items are you want to use particular food basic components or else... there is no specific rules as laid down, however, canteen should be a place very important in the hygienic point, health of working men/women etc.,
best of luick...